14 DAY TRIAL // Duke University researchers have managed to modify an existing method of growing very long, straight and aligned carbon nanotubes, in that they can now obtain near-perfect samples of carbon semiconductors, at the billionth-of-a-millimeter scale. This means that future electronic devices will more likely not feature older building technologies for their circuits, but, rather, connections between the parts will be made up of these tubes. They are very flexible and long, and can withstand the requirements of such tasks, the team behind the study says.
"I think it's the holy grail for the field," Jie Liu, Duke's Jerry G. and Patricia Crawford Hubbard professor of Chemistry, maintains. "Every piece is now there, including the control of location, orientation and electronic properties all together. We are positioned to make large numbers of electronic devices such as high-current field-effect transistors and sensors," Liu explains. Alongside colleagues from Peking University in China, the researchers have published their finds in the January 20 issue of the research journal Nano Letters.
Lei Ding, a post doctoral researcher in Liu's lab, authored the first study on the theme, published in the Journal of the American Chemical Society (JACS) on April 16th, 2008. In the paper, the researcher details how the team then used filaments of quarts crystals to force the nanotubes to grow in a straight line, so as to prevent entanglement and loss of current as well. The main goal of the research is to endow the nanotubes with the property to carry high-frequency charges, such as those used in transistors.
"Operating at higher frequencies means they would be much better devices for wireless communications," Liu adds. "We found that by using the right combination of two alcohols with the argon and hydrogen [used to 'nourish' nanotubes] we could grow exclusively semiconducting nanotubes. It was like operating a tunig knob. We have estimated from measurements that samples consisted of 95 to 98 percent semiconducting nanotubes."